Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI) On-Orbit Wind Observations: Data Analysis and Instrument Performance.

The design, principles of operation, calibration, and data analysis approaches of the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) on the NASA Ionospheric Connection (ICON) satellite have been documented prior to the ICON launch. Here we update and expand on the MIGHTI wind data analysis and discuss the on-orbit instrument performance. In particular, we show typical raw data and we describe key processing steps, including the correction of a "signal-intensity dependent phase shift," which is necessitated by unexpected detector behavior. We describe a new zero-wind calibration approach that is preferred over the originally planned approach due to its higher precision. Similar to the original approach, the new approach is independent of any a priori data. A detailed update on the wind uncertainties is provided and compared to the mission requirements, showing that MIGHTI has met the ICON mission requirements. While MIGHTI observations are not required to produce absolute airglow brightness profiles, we describe a relative brightness profile product, which is included in the published data. We briefly review the spatial resolution of the MIGHTI wind data in addition to the data coverage and data gaps that occurred during the nominal mission. Finally, we include comparisons of the MIGHTI wind data with ground-based Fabry-Perot interferometer observations and meteor radar observations, updating previous studies with more recent data, again showing good agreement. The data processing steps covered in this work and all the derived wind data correspond to the MIGHTI data release Version 5 (v05).

Calibration lamp design, characterization, and implementation for the Michelson Interferometer for Global High-Resolution Thermospheric Imaging instrument on the Ionospheric Connection satellite.

We describe the design and ground-based performance of the two-color calibration lamp for the Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI) instrument on the NASA Ionospheric Connection (ICON) satellite. The calibration lamp assembly contains radio frequency excited krypton and neon lamps, which generate emission lines at 557 and 630 nm, respectively, and which are used to monitor thermal drifts in the two MIGHTI Doppler asymmetric spatial heterodyne interferometers. The lamps are coupled to two mixed optical fiber bundles that deliver the calibration signals to the two MIGHTI optical units. The assembly starts reliably, consumes <8 W, and has passed environmental testing for the ICON satellite. The total mass of the lamp assembly is 1.8 kg. Special features of the assembly and its implementation are described along with results of life tests.

Fractures in older adults. A view of the future?

INTRODUCTION: It is accepted that the incidence of fractures in patients aged ≥ 65 years is increasing but little is known about which fractures are becoming more common in this group of patients. Virtually all research has concentrated on the classic fragility fractures of the proximal femur, proximal humerus, pelvis, spine and distal radius but it is likely that other fractures are becoming more common. METHODS: We have examined two prospectively collected databases 10 years apart to see which fractures are becoming more common in ≥ 65 year old patients. We compared the fractures to look for epidemiological differences over the 10-year period and we compared the epidemiology of the fractures that had increased in incidence with equivalent fractures in the < 65 year old population. RESULTS: Analysis shows that in older female patients fractures of the clavicle, finger phalanges, ankle and metatarsus are increasing in incidence. In males there is an increasing incidence of fractures of the proximal humerus, distal humerus, metacarpus, pelvis, femoral diaphysis, distal tibia and ankle. In females the basic epidemiology of fractures in the ≥ 65 year old population was very similar to the fractures seen in younger females and we believe that the increasing incidence of fractures in the future will mainly be low velocity fractures following falls. In older males however, it is apparent that there is a much wider variation in the causes of fracture. DISCUSSION: We believe that the changes in fracture epidemiology in older patients relate to improved health and longevity and analysis of our population during the study period shows significant social changes which are associated with increased longevity and improved health. It is probable that fractures in older patients will continue to increase in incidence and that other fractures that are now commonly seen in middle-aged patients will be seen in older patients. Surgeons will have to treat more complex fractures in older males than in older females and it is likely that there will be a higher incidence of open and multiple fractures. Appropriate management techniques will need to be established.

Retrieval of Lower Thermospheric Temperatures from O2 A Band Emission: The MIGHTI Experiment on ICON.

The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) is a satellite experiment scheduled to launch on NASA's Ionospheric Connection Explorer (ICON) in 2017. MIGHTI is designed to measure horizontal neutral winds and neutral temperatures in the terrestrial thermosphere. Temperatures will be inferred by imaging the molecular oxygen Atmospheric band (A band) on the limb in the lower thermosphere. MIGHTI will measure the spectral shape of the A band using discrete wavelength channels to infer the ambient temperature from the rotational envelope of the band. Here we present simulated temperature retrievals based on the as-built characteristics of the instrument and the expected emission rate profile of the A band for typical daytime and nighttime conditions. We find that for a spherically symmetric atmosphere, the measurement precision is 1 K between 90-105 km during the daytime whereas during the nighttime it increases from 1 K at 90 km to 3 K at 105 km. We also find that the accuracy is 2 K to 11 K for the same altitudes. The expected MIGHTI temperature precision is within the measurement requirements for the ICON mission.

Tibial Fracture Nonunion and Time to Healing After Reamed Intramedullary Nailing: Risk Factors Based on a Single-Center Review of 1003 Patients.

OBJECTIVE: To determine factors associated with nonunion of adult tibial fractures. DESIGN: Retrospective review with data collection for logistic regression and survival analysis. SETTING: Scottish Level I trauma center, 1985-2007. PATIENTS: During this period, 1590 adult tibial fractures were treated by reamed nailing and 1003 fractures met all inclusion criteria for the chosen analysis. INTERVENTION: Reamed intramedullary nailing. MAIN OUTCOME MEASURES: Record of nonunion diagnosis and final union time with characteristics, including age, gender, closed or open injury, OTA/AO classification, Gustilo classification, fasciotomy, infection, polytrauma, smoking, and injury severity score. RESULTS: The overall nonunion rate was 12%, and median time to healing was 18 weeks. Age significantly influenced nonunion, with middle-aged patients at highest risk. Both fracture type (closed/open) and morphology (OTA/AO classification) significantly influenced nonunion risk and time to union. Among closed injuries, the highest nonunion rate was for OTA/AO type B fractures (15%). Among open injuries, the highest nonunion rate was for OTA/AO type C (61%). Both compartment syndrome and smoking did not significantly influence nonunion risk but did significantly extend time to union. CONCLUSIONS: Injury characteristics including fracture morphology and severity of soft tissue injury were strong predictors of compromised fracture healing. Age also influenced nonunion risk in an unexpected way, with highest rates in the middle decades of adulthood. Future studies should consider the possibility of similar age-related effects and clinical studies should seek to identify explanations for why this may arise, including both physiological and socio-behavioral factors. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The changing epidemiology of open fractures in vehicle occupants, pedestrians, motorcyclists and cyclists.

AIMS: To investigate the changing epidemiology of open fractures in vehicle occupants, pedestrians, motorcyclists and cyclists. MATERIALS AND METHODS: Data on all non-spinal open fractures admitted to the Royal Infirmary of Edinburgh after a road traffic accident between 1988 and 2010 were collected and analysed to provide information about the changing epidemiology in different patient groups. Demographic information was collected on all patients with the severity of injury being analysed with the Injury Severity Score (ISS), Musculoskeletal Index (MSI) and the number of open fractures. The severity of the open fractures was analysed using the Gustilo classification. The 23-year study period was divided into four shorter periods and the results were compared. RESULTS: There were 696 patients treated in 23 years. Analysis showed that the incidence of RTA open fractures initially fell in both males and females and continued to fall in females during the 23 years. In males it levelled off about 2000. The age of the female patients also fell during the study period but it did not change in males. The only patient group to show an increased incidence of open fractures were cyclists. In vehicle occupants the incidence fell throughout the study period but it levelled off in pedestrians and motorcyclists. There was no difference in the severity of injury in any group during the study period. The most severe open fractures were those of the distal femur and femoral diaphysis although open tibial diaphyseal fractures were the most common fracture in all patient groups. CONCLUSIONS: Improved car design and road safety legislation has resulted in a reduction in the incidence of open fractures in vehicle occupants, pedestrians and motorcyclists. The most obvious group to have benefitted from this are older female pedestrians. The only group to show an increase in age during the study period were male motorcyclists.

Plate Versus Tension-Band Wire Fixation for Olecranon Fractures: A Prospective Randomized Trial.

BACKGROUND: The aim of this single-center, single-blinded, prospective randomized trial was to compare the outcomes of tension-band wire (TBW) and plate fixation for simple isolated, displaced fractures of the olecranon. METHODS: We performed a prospective randomized trial involving 67 patients who were ≥16 to <75 years of age and had an acute isolated, displaced fracture of the olecranon. Patients were randomized to either TBW (n = 34) or plate fixation (n = 33) and were evaluated at 6 weeks, 3 months, 6 months, and 1 year following surgery. The primary outcome measure was the Disabilities of the Arm, Shoulder and Hand (DASH) score at 1 year. RESULTS: The baseline demographic and fracture characteristics of the 2 groups were comparable, except for age, which was lower in the TBW group. The 1-year follow-up rate was 85% (n = 57), with 84% (n = 56) completing the DASH. There was a significant improvement in the DASH score over the 1-year period following surgery (p < 0.001). At 1 year, the DASH score for the TBW group (12.8) did not differ significantly from that of the plate group (8.5) (p = 0.315). The groups also did not differ significantly in terms of range of motion, the Broberg and Morrey score, the Mayo Elbow Score, or the DASH at all assessment points over the 1 year (all p ≥ 0.05). Complication rates were significantly higher in the TBW group (63% compared with 38%; p = 0.042), predominantly because of a significantly higher rate of metalwork removal in symptomatic patients (50.0% compared with 22%; p = 0.021). Four infections occurred, all in the plate group (0% versus 13%; p = 0.114), as did 3 revision surgeries (0% versus 9.4%; p = 0.238). CONCLUSIONS: Among active patients with a simple isolated, displaced fracture of the olecranon, no difference was found between TBW and plate fixation in the patient-reported outcome at 1 year following surgery. The complication rate was higher following TBW fixation and was due to a higher rate of implant removal in symptomatic patients. However, the more serious complications of infection and the need for revision surgery occurred exclusively following plate fixation in this trial. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Epidemiology of open fractures in sport: One centre's 15-year retrospective study.

AIM: To describe the epidemiology of sport-related open fractures from one centre's adult patient population over a 15-year period. METHODS: A retrospective review of a prospectively-collected database was performed: The database contained information all sport-related open fractures, sustained from 1995 to 2009 in the Edinburgh, Mid and East Lothian Populations. RESULTS: Over the 15-year period, there were 85 fractures recorded in 84 patients. The annual incidence of open sport-related fractures was 0.01 per 1000 population. The mean age at injury was 29.2 years (range 15-67). There were 70 (83%) males and 14 females (17%). The 6 most common sports were soccer (n = 19, 22%), rugby (n = 9, 11%), cycling (n = 8, 9%), hockey (n = 8, 9%); horse riding (n = 6, 7%) and skiing (n = 6, 7%). The five most common anatomical locations were finger phalanges (n = 30, 35%); tibial diaphysis (n = 19, 23%); forearm (n = 12, 14%); ankle (n = 7, 8%) and metacarpals (n = 5, 6%). The mean injury severity score was 7.02. According to the Gustilo-Anderson classification system, 45 (53%) fractures were grade 1; 28 (33%) fractures were grade 2; 8 (9%) fractures were grade 3a; and 4 (5%) fractures were grade 3b. Out of the total number of fractures, 7 (8%) required plastic surgical intervention as part of management. The types of flaps used were split skin graft (n = 4), fasciocutaneous flaps (n = 2); and adipofascial flap (n = 1). CONCLUSION: We analysed the epidemiology of open fractures secondary to sport in one centre over a 15-year period. Soccer and rugby were the most common causative sports while fractures of the finger phalanx and of the tibial diaphysis were the most common sites. Open fractures are uncommon in sport; however, when they are sustained they usually occur on muddy sport fields or forest tracks and therefore must be treated appropriately. It is important that clinicians and sports therapists have knowledge of these injuries, in order to ensure they are managed optimally.

High-efficiency echelle gratings for MIGHTI, the spatial heterodyne interferometers for the ICON mission.

Development of a new generation of low-groove density-blazed echelle gratings optimized for MIGHTI, a space-borne spatial heterodyne interferometer operating in the visible and near infrared is described. Special demands are placed on the wavefront accuracy, groove profile, and efficiency of these gratings. These demands required a new ruling for this application, with significant improvements over existing gratings. Properties of a new generation of highly efficient, plane gratings with 64 grooves/mm blazed at 8.2° are reported.

Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI): Instrument Design and Calibration.

The Michelson Interferometer for Global High-resolution imaging of the Thermosphere and Ionosphere (MIGHTI) instrument was built for launch and operation on the NASA Ionospheric Connection Explorer (ICON) mission. The instrument was designed to measure thermospheric horizontal wind velocity profiles and thermospheric temperature in altitude regions between 90km and 300km, during day and night. For the wind measurements it uses two perpendicular fields of view pointed at the Earth's limb, observing the Doppler shift of the atomic oxygen red and green lines at 630.0nm and 557.7nm wavelength. The wavelength shift is measured using field-widened, temperature compensated Doppler Asymmetric Spatial Heterodyne (DASH) spectrometers, employing low order échelle gratings operating at two different orders for the different atmospheric lines. The temperature measurement is accomplished by a multichannel photometric measurement of the spectral shape of the molecular oxygen A-band around 762nm wavelength. For each field of view, the signals of the two oxygen lines and the A-band are detected on different regions of a single, cooled, frame transfer charge coupled device (CCD) detector. On-board calibration sources are used to periodically quantify thermal drifts, simultaneously with observing the atmosphere. The MIGHTI requirements, the resulting instrument design and the calibration are described.

Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI): Monolithic Interferometer Design and Test.

The design and laboratory tests of the interferometers for the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument which measures thermospheric wind and temperature for the NASA-sponsored Ionospheric Connection (ICON) Explorer mission are described. The monolithic interferometers use the Doppler Asymmetric Spatial Heterodyne (DASH) Spectroscopy technique for wind measurements and a multi-element photometer approach to measure thermospheric temperatures. The DASH technique and overall optical design of the MIGHTI instrument are described in an overview followed by details on the design, element fabrication, assembly, laboratory tests and thermal control of the interferometers that are the heart of MIGHTI.

Open Finger Fractures: Incidence, Patterns of Injury and the Influence of Social Deprivation.

BACKGROUND: This study investigates the patterns and epidemiology of open finger fractures. There is little good data about these injuries. METHODS: Data were collected prospectively in a single trauma unit serving a well-defined population. RESULTS: Over a 15 year period 1090 open finger fractures were treated in 1014 patients. These made up the vast majority of open fractures treated in the trauma unit during this period. The incidence of open finger fractures was 14.0 per 100,000 patients per year. Deprivation did not influence the incidence of open finger fractures but did affect treatment choices for women. Most open finger fractures resulted from crush injuries or falls and required only simple operative treatments: debridement, lavage and early mobilization. CONCLUSIONS: Open finger fractures formed the majority of the workload of open fractures at our trauma centre but usually required simple treatments only. Social deprivation was not shown to influence the patterns or epidemiology of these injuries but did affect treatment choices for women.

Incidence and Epidemiology of Patellar Fractures.

The literature lacks large-scale, up-to-date, population-based epidemiology studies on the incidence of patellar fractures based on complete populations. The purpose of this study was to provide up-to-date information concerning the incidence of patellar fractures in a large and complete population spanning a decade and to report on the distribution of fracture classification, trauma mechanisms, and patient baseline demographics. A retrospective review of clinical and radiological records of 756 patellar fractures treated between 2005 and 2014 was conducted. Mean age at the time of fracture was 54±21 years. Mean age was 46±22 years for males and 61±18 years for females. The sex distribution was 425 (56%) females and 331 (44%) males. The incidence of patellar fractures between 2005 and 2014 was 13.1/100,000/ year with a year-to-year variation between 10.5 and 16.5/100,000/year during the 10-year observation period. The distribution of incidence shows an increase with increasing age. Males have the highest incidence of fracture in the 10-to-19-year age group, approximately 15.4/100,000/year. Females in the 60-to-80-year age group have the highest incidence, approximately 36/100,000/year. AO type 34-C3 was the most common fracture type, representing 25% of all patellar fractures, followed by AO type 34-C1, representing 23%. [Orthopedics. 2016; 39(6):e1154-e1158.].

Global Forum: Fractures in the Elderly.

Fractures in the elderly are increasing in incidence and becoming a major health issue in many countries. With an increasing number of the elderly living to an older age, the problems associated with fractures will continue to increase. We describe the epidemiology of fractures in the elderly and identify six fracture patterns in the population of patients who are sixty-five years of age or older. We also analyzed multiple fractures and open fractures in the elderly and we show that both increase in incidence with older age. The incidence of open fractures in elderly women is equivalent to that in young men. Many factors, including patient socioeconomic deprivation, increase the incidence of fractures in the elderly. More than 90% of fractures follow low-energy falls and the mortality is considerable. Mortality increases with older age and medical comorbidities, but there is also evidence that it relates to premature discharge from the hospital.

Spatial heterodyne spectroscopy at the Naval Research Laboratory.

Spatial heterodyne spectroscopy (SHS) is based on traditional Michelson interferometry. However, instead of employing retro-reflectors in the interferometer arms, one or both of which are moving, it uses fixed, tilted diffraction gratings and an imaging detector to spatially sample the optical path differences. This concept allows high-resolution, high-throughput spectroscopy without moving interferometer parts, particularly suitable for problems that require compact, robust instrumentation. Here, we briefly review about 20 years of ground- and space-based SHS work performed at the U.S. Naval Research Laboratory (NRL), which started with a visit by Prof. Fred Roesler to NRL in 1993.

The role of primary plastic surgery in the management of open fractures.

A study was undertaken to determine the requirement for primary plastic surgery in the treatment of open fractures. We reviewed 3297 consecutive open fractures in a 22-year period in a defined population. Analysis showed that 12.6% of patients required primary plastic surgery with 5.6% being treated with split skin grafting and 7.2% with a flap. Only 3.5% of open upper limb fractures required primary plastic surgery compared to 27.9% of open lower limb fractures. The fractures that required most primary plastic surgery were those of the femoral diaphysis and all fractures between the proximal tibia and the midfoot. The incidence of open fractures that require primary plastic surgery was 28/10(6)/year. The incidence in open upper and lower limb fractures was 5.3/10(6)/year and 22.7/10(6)/year respectively. Using these figures it is possible to estimate the numbers of open fractures that will require primary plastic surgery each year in the United Kingdom.

Predictors of Compartment Syndrome After Tibial Fracture.

OBJECTIVES: The aim of our study was to identify the risk factors associated with the development of acute compartment syndrome (ACS) after a fracture of the tibia. DESIGN: Retrospective cohort study. SETTING: Orthopaedic trauma unit, university teaching hospital. PATIENTS: From our trauma database, we identified all patients who sustained an acute tibial diaphyseal fracture over a 13-year period. A retrospective analysis of 1407 patients was performed to record and analyze the OTA fracture classification, open fracture grade according to Gustilo, soft tissue injury classification according to Tscherne, treatment, development of ACS, and other patient demographics including smoking, occupation, and socioeconomic deprivation. MAIN OUTCOME MEASURE: A diagnosis of ACS was made using clinical signs, compartment pressure monitoring, or a combination of the 2. RESULTS: One thousand three hundred eighty-eight patients were included with a mean age of 39 (12-98) years, and 957 (69%) were male. One hundred sixty patients (11.5%) were diagnosed with ACS. On initial analysis, age, male gender, blue-collar occupation, sporting injury, fracture classification, and treatment with intramedullary nails were predictive of ACS (all P < 0.05). Age was the strongest predictor of developing ACS (P < 0.001), with the highest prevalence between 12-19 years and 20-29 years. Occupation (P = 0.01) and implant type (P = 0.004) were the only factors that remained significant after adjusting for age. On further subanalysis, implant type was not predictive when stratified by Tscherne class (P = 0.11). CONCLUSIONS: We have documented the risk factors for the development of ACS after an acute tibial diaphyseal fracture, with youth the strongest predictor. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Open ankle fractures: who gets them and why?

Open ankle fractures present a significant clinical challenge. The management and outcome of these injuries has been extensively reported, but there have been no reports of the epidemiology and how this has changed over time. We report 178 adult patients with open ankle fractures presenting to our unit over a twenty-three year period. The study centre is the only hospital receiving adult orthopaedic trauma in the region and has a defined population. The incidence of open ankle fractures was 1.5/10(5)/year, representing 1.5 % of all ankle fractures. The mean age was 55 years (range 16-96), with the highest incidence occurring in women over the age of 90. The most common mechanism was a simple fall with only 26 % of cases due to a motor vehicle collision (MVC). 82 % of cases were isolated injuries. Social deprivation had no significant influence on the incidence, but there was a difference in the mechanism with the majority of injuries in the most deprived quintile caused by MVCs and significantly fewer due to simple falls (p = 0.047). Over the twenty-three years, there was a significant increase in the mean age from 44 to 64 years (p = 0.03). The overall incidence remained constant over the two decades. In common with many traumatic injuries, open ankle fractures are increasingly low-energy insufficiency fractures affecting elderly patients, particularly older women. This has implications for service planning and training as well as the surgical intervention in these patients.

Predictors of poor clinical outcome following hip fracture in middle aged-patients.

The aim of this study was to investigate morbidity and mortality following hip fractures in middle aged patients. In addition, we aimed to identify risk factors which could be used to predict postoperative complications. All patients aged 40-55 who sustained a hip fracture in Lothian from 2007 to 2008 were identified from a prospective trauma database. The main outcomes were complications and 5-year mortality. Thirty hip fractures were included in the study. Complications occurred in nine (30%) cases. Deep infection was seen in three cases (10%). Mortality was 20% at 5 years, 26 times higher than for the general population. All surviving patients were contacted for risk factor analysis (24). Low energy fractures, alcohol excess, smoking and history of previous fractures were significantly associated with complications (p<0.05). Complications only occurred amongst low energy fractures. Risk factors were further analysed using the WHO FRAX algorithm. No patient with a FRAX score of less than 10 suffered a complication, whereas 50% of patients who had a FRAX score of more than 10 suffered a complication. The results of our study suggest that low energy hip fractures in middle age are due to underlying morbidity and are associated with a high incidence of postoperative complications and mortality. The FRAX score could be used as a simple method of identifying patients in this age group who are at risk of a poor outcome.

Open fractures in the elderly. The importance of skin ageing.

Open fractures in the elderly are rare and there is little information about them. We have reviewed 484 open fractures in patients aged ≥65 years over a 15-year period and compared them with 1902 open fractures in patients <65 years treated in the same period. The incidence of open fractures increased significantly with age. The incidence of open fractures in patients aged <65 years was 296.6/10(6)/year compared which increased to 332.3/10(6)/year in patients aged ≥65 years and further still to 446.7/10(6)/year in the super-elderly aged ≥80 years The fracture distribution curves show that males aged 15-19 years and females aged ≥90 years have a very similar incidence of open fractures. In males the incidence declines almost linearly, whereas in females there is a steady increase in fracture incidence with age until the 7th decade of life when the incidence rises sharply. About 60% of open fractures in the elderly follow a fall and most fractures are caused by low energy injuries. Despite this there is a high incidence of Gustilo Type III fractures, particularly in females. The commonest open fractures in females are those of the distal radius and ulna, fingers, tibia and fibula and ankle, all fractures with subcutaneous locations. It has been shown that ageing alters the mechanical properties of skin and we believe that this accounts for the increased incidence of open fractures in elderly females which occurs about 1 decade after the post-menopausal increase in fracture incidence.